txt record for exchange organization

Hi,

I am searching on how to get information and how to correctly create txt record in the external DNS to prevent mail spoofing for my accepted domains

currently I have one exchange organization and I have 4 accepted domains which I want to create txt records for them.all I found is related to office 365 not related to hosted Exchange 2013.

I need to et this information to provide it to public dns provider

Mashhour Faraj